such as the passage of food and stress. Other research-
ers suggest that there is a flaw in the way the brain and
the gut interact. Some suggest that an earlier infection
predisposes some people to develop IBS. Other
researchers have found that there are abnormal num-
bers of receptors for the neurotransmitter serotonin in
the gastrointestinal tract of people with IBS. Neuro-
transmitters are chemicals that carry nerve impulses
from one nerve to another. Abnormal levels of these
chemicals could make the bowel more reactive. In fact,
low doses of some antidepressant drugs that affect
serotonin levels improve IBS symptoms in some
people.
Whatever the cause, symptoms of IBS include
pain or discomfort in the abdomen, feeling bloated
or having a lot of gas, diarrhea, constipation, or alter-
nating periods of both, and mucus in the stool. The
symptoms come and go and can change in a single
individual over time. The impact of symptoms can
range from mild to severe, and the intensity of symp-
toms can also change over time. Symptoms are usually
reduced or relieved by a bowel movement.
Although they are not the cause of IBS, certain
things can trigger symptoms. Triggers vary from per-
son to person.
Food. Different foods are triggers for different peo-
ple. Some common trigger foods are dairy products,
sorbitol (a sweetener used in sugar-free products),
foods containing caffeine, chocolate, and alcohol.
Stress. Stress from any source often triggers or wor-
sens symptoms in people with IBS.
Illness. Other gastrointestinal illnesses caused by
bacteria or viruses can trigger symptoms.
Menstruation. Women seem to have more severe
symptoms when they are menstruating, suggesting
that changing hormone levels may affect symptoms.DiagnosisThere are no tests for IBS. As a result, there are
two different ways to arrive at a diagnosis of IBS. One
is to perform tests to specifically eliminate other dis-
orders with similar symptoms, such as ulcerative col-
itis. When other possible disease have been eliminated,
then IBS is diagnosed.
The other approach to diagnosis is to use what is
known as the Rome criteria for diagnosis. Following
the Rome criteria, IBS is diagnosed if the symptoms of
abdominal pain, diarrhea and/or constipation are
present for at least 12 weeks (the weeks do not have
to be consecutive) and several of the following con-
ditions are met:A change in the frequency of bowel movements
A change in the consistency of the stool
Straining to empty the bowels or a feeling or urgency
to empty the bowels
Frequently feeling that the bowel is not completely
empty
Mucus in the stool
Bloating
Symptoms are reduced by having a bowel movement.
Note that blood in the stool, vomiting, fever, and
diarrhea that awakens a person at night are not symp-
toms of IBS. Individuals with these symptoms should
see a doctor promptly.
Often these two approaches to diagnosis are com-
bined, and the physician may initially perform a sig-
moidoscopy or a colonoscopy to look at the inside of
the bowel. In these procedures, a tube called an endo-
scope is inserted through the rectum and into the
colon. At the end of the endoscope is a tiny camera
that allows the doctor to see if there is damage to the
cells lining digestive tract. During this procedure, the
doctor also removes small tissue samples (biopsies) in
order to look for abnormal cells under the microscope.
This can eliminate inflammatory bowel syndrome as
the cause of symptoms.
The doctor may also do a lactose intolerance test.
Lactose is a sugar found in milk. People who lack the
enzyme to break down this sugar have symptoms sim-
ilar to those of irritable bowel syndrome. Lactose
intolerance is common, and a lactose intolerance test
can confirm or eliminate lactose as the source of the
symptoms.
The doctor may also do a blood test to determine
if symptoms are caused by early or mild celiac disease.
People with celiac disease are sensitive to gluten, a
proteinfound in wheat, barley, rye, and the products
made from these grains. Eating foods containing glu-
ten often causes symptoms similar to IBS in people
with celiac disease.TreatmentBecause no functional problems can be found in
people with IBS, family members and even some
healthcare providers may be inclined to dismiss symp-
toms as caused by emotional problems or similar psy-
chological upsets. However, the disease is real and not
something that the patient can control. Finding a
doctor with whom the patient can establish good com-
munication and feel comfortable is an important first
step in treatment.Irritable bowel syndrome